1. Field of the Invention
The present invention relates to an apparatus and method for producing a floor mat provided on its reverse side with a group of projections having flat areas on their tips so as to improve the effect of prevention of sliding or shifting of position. The floor mat obtained by the apparatus and method of the present invention is useful, for example, as a floor mat for a car or a floor mat for the home or office.
2. Description of the Related Art
Hitherto, a group of projections was provided on the reverse surface of the mat so as to prevent the slide of a car floor mat, a door mat or the like. For example, as shown in FIG. 1, a conventional car floor mat 1 may be composed of a surfacing sheet 2 comprising a carpet or the like, a substrate sheet 3 comprising an elastic soft material (for example, a thermoplastic resin), and projections 4 on the reverse surface of the substrate sheet 3. In the case of a car floor mat composed of only an elastic soft material or the like without a surfacing sheet, a similar group of projections was provided on the reverse surface. The frictional resistance between the tips of the group of projections and the floor surface can prevent movement or sliding. The shape of the projections is generally preferably a frustum with a smooth flat area at the tip.
When producing a mat having such projections, a pair of rolls as shown in FIG. 2 was generally used. That is, a molding resin material 3a supplied from a resin supply means 5 was passed through the nip between a press roll 6 and a mold roll 7 contacting each other in parallel, and was laminated with a surfacing sheet material 2a supplied from the press roll 6 side. On the surface of the mold roll 7, depressions 8 corresponding to the molds of the projections 4 were formed. Thus, the heated and softened molding resin material 3a was pushed into these depressions 8. Because the mold roll 7 had a cooling means 9, the molding resin material 3a in the depressions 8 was gradually cooled and formed, and then pulled out from the depressions 8 along with the rotation of the press roll 6 and the mold roll 7 to form a floor mat having projections 4 on the reverse surface.
In the conventional mold roll 7, however, no means was provided for venting the air in the depressions 8 of the molds. Therefore, as shown in FIG. 3, when the heated and softened molding resin material 3a was pushed into the depressions 8, air was compressed at the innermost parts of the depressions 8, and thus spaces 8a were formed. Accordingly, even if the bottom surfaces of the depressions 8 as the molds were flat, the form of the tips 3b of the projections did not become flat, but spherical.
As above, in the conventional method for production of a floor mat, it was not possible to form projections having a shape exactly corresponding to the shape of the depressions 8 of the molds. Strictly speaking, the shapes of the projections were diverse. Further, it was substantially impossible or extremely difficult to stably form a group of projections having flat surfaces on their tips. In addition, a floor mat having a group of projections with spherical tips did not give rise to a sufficient frictional resistance and was not satisfactory in terms of the effect of preventing sliding or shifting of position.